Let's Make Robots!

Breadboard Basics


This walkthrough is meant for someone who has never used a breadboard before. When complete you should be able to make a basic circuit (light an LED).

List of items:

  1. Breadboard
  2. Small wires with both ends stripped (22 gauge works well). 
  3. 5volt battery (4AA batteries, easy to fit together with a battery box)
  4. 1/4watt 330 ohm resistor (to keep that LED from burning out)
  5. LED any color

A breadboard is used to prototype circuits. You can use it to test them out before you use a project board and solder it into place. This saves time and money if you make mistakes. You can take a piece out and pop a new one in quickly. Not so if you solder everything into place then it doesn't work.

This is a breadboard:

breadboard.jpg

This is a breadbox:

breadbox.jpg

And this is a rooster:

rooster.jpg

 

Now that we have that out of the way lets move on to something more exciting...

Breadboards come in many different sizes. You can get one much bigger or much smalle than the one above. This one is just about the right size for small to medium circuits. I got it from RadioShack, but any store or online store should have them if they carry LEDs, resistors, motors, etc.

This is a drawing showing how the holes are connected:

boardcircuit.gif

Notice the board is divided into two halves (top and bottom). The first row is generally used for voltage (positive, V, +, etc). The second row is usually used for negative (0, -V, -, etc). Below is a breadboard with 2 wires connected. Note that the top wire would be connected to the positive terminal on a batter and the second wire would connect to a negative.When this is done the top row would all be positively charged and thesecond row negatively charged. The red line shows positive and the black line shows negative.

battery.jpgbattery.JPG

Now lets add a resistor to move current to one of the columns:

resistor.jpg

This resistor is 1/4watt 330 ohm. It basically limits the current so that it doesn't burn out the LED that we will add later. Note that once we added one end of it into the positive row and th eother end onto one of the columns, that column becomes positvely charged.

Now to add a column for ground:

negative.jpg

The blue wire connects the negative row (ground) to an unused column. DO NOT USE THE SAME COLUMN AS THE POSITIVE. It will just complete the circuit without doing anything. Notice the red and black vertical lines. When we add an LED we can complete the circuit.

addled.jpg

The LED has the positive lead (it is usually longer than the ground lead) in one of the holes of the positive columns and the other lead in the ground (negative) column.

Sideview:

sideview.jpg

Once we add the battery to the orange wires...

lit.jpg

If you didn't get any light make sure your battery is connected so that the positive terminal is connected to the wire on the top of the breadboard and that the groudn terminal (negative) is connected to the second row of the breadboard.

A few things to note:

  • Most breadboards have a top and bottom. We only used the top. The bottom half is below that indentation. It in effect splits the breadboard in two. This is so you can use chips that require you to use both sides. I will eventually get to that in later tutorials.
  • The resistor I used was for a 5volt battery. I used 4AA batterys which is close to 5 volts. If you use a 9volt battery you will need a different resistor.
  • I don't claim to be an expert. I just learned this stuff a week or two before I wrote the tutorial. Feel free to make suggestions, changes, correct my spelling, etc. When I learn more stuff I'll post a quick tutorial so you can learn from my mistakes!

 

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 jklug80,

By checking your tutorial and seeing everyone's comments your tutorial should be a god start for beginner like me but could you reupload the images please!

Thanks,

Shojiki,

Hey, it is possible to reupload the images? Thanks :)

but the rooster creeped me out. LOL
I love you.
Nice simply and well made..!XD
very nice.. keep it going =]

Sweet someone I can learn from and share ideas ;) I actually just added the PICAXE 21x1 and a stereo socket to my board and got code to transfer and the little light to blink. Now to add a servo! This really isn't that hard if you take time to look at schematics for the processor and other components and take your time. Of course I haven't done anything hard yet.

Don't sweat the petty things. Don't pet the sweaty things.

Thanks for the kind words ;) I just read through a few tutorials online to figure out the basics. I got some small projects working using the project board, but I want to move them over to a breadboard (is that backwards?!?). Once I get a bit further I'll add another tutorial on how to use picaxe with a breadboard and get that light blinking!

Don't sweat the petty things. Don't pet the sweaty things.

I think the current should be less than 15ma. Measure the voltage drop across R (resister) and divide that value by the 330. The forward voltage across LED must be taken into account. The equation is Supply voltage is Vb = Vr+ Vled. Where Vb is the supply voltage or battery voltage here. The voltage across the resister is Vr and the Vled is the forward voltage of the LED. Therefore 5v = Vr + 1 or 2 volts of forward voltage of the LED. The voltage across R or Vr is derived by 5 - 1 or 2 ~= 4 or 3 volts. The current flows through the circuit should be around 4/330 or 3/330 which are 12ma or 10ma.

Regards,

-Pandit

The LEDs I bought said 15ma. I am assuming that is the max so 12 or 10 would ensure it didn't get fried.

Don't sweat the petty things. Don't pet the sweaty things.